1. Field of the Invention
This invention relates to a connector.
2. Description of the Related Art
Conventionally, there has been proposed a connector that is arranged between two printed circuit boards 961 and 962 (see FIG. 15), and electrically connects the two printed circuit boards 961 and 962 (see Japanese Laid-Open Patent Publication (Kokai) No. 2002-313460). This connector will be described with reference FIGS. 13 to 15.
The connector comprises an insulator 950 and a plurality of contacts 901 each having a spring structure, which are held by the insulator 950.
The insulator 950 is formed with a plurality of contact accommodation spaces 952 for movably accommodating the contacts 901, respectively. The contact accommodation spaces 952 extend through the insulator 950 in a direction D of connecting the printed circuit boards 961 and 962 (direction of connecting objects to be connected). The insulator 950 is formed with a contact restricting portion 953 extending through each contact accommodation space 952. The contact restricting portion 953 is a portion for restricting the amount of movement of the contact 901.
Each contact 901 is formed by molding a metal plate into a substantially W-shape by press processing. More specifically, opposite ends of the contact 901 are each bent into an arcuate shape to thereby form contact portions 902 and 903 which can be brought into contact with connection pads (not shown) of the printed circuit boards 961 and 962, respectively. An intermediate portion of the contact 901 is bent to form a holding portion 904 that can surround substantially the whole periphery of the contact restricting portion 953. Spring portions 910 and 911 which are elastically deformable in the connection direction D are located between the holding portion 904 and the two contact portions 902 and 903, respectively. Portions integrally connecting the holding portion 904 and the spring portions 910 and 911, respectively, are each bent back into an arcuate shape to form two bent-back portions (curving portion) 910A and 911A. A dimension of a gap 912 between the bent-back portions 910A and 911A in the connection direction D is smaller than a dimension L of the contact restricting portion 953 in the connection direction D. The two contact portions 902 and 903 protrude out of the contact accommodation space 952 of the insulator 950, respectively.
A description will be given of how to use the connector with reference to FIGS. 14 and 15. The connector is used in a state press-fitted in a press-fitting hole 921 of a frame 920 in advance. The press-fitting hole 921 is larger in length in the connection direction D than each contact accommodation space 952. The contact portions 902 and 903 of each contact 901 protrude out of the press-fitting hole 921 in a state in which the connector has been press-fitted in the press-fitting hole 921 of the frame 920.
First, positioning of the connector is performed such that the contact portions 903 of the contacts 901 are positioned on the contact pads of the lower printed circuit board 962, respectively. Next, in this state, the connector is moved down along the connection direction D. After the connector is thus arranged in a predetermined position on the lower printed circuit board 962, positioning of the upper printed circuit board 961 is performed such that the contact pads of the upper printed circuit board 961 are positioned on the contact portions 902 of the contacts 901, respectively. Finally, in this state, the upper printed circuit board 961 is moved down along the connection direction D. At this time, both the spring portions 910 and 911 of the contacts 901 are almost equally bent, and both the contact portions 902 and 903 of the contacts 901 are pressed against the contact pads of the printed circuit boards 961 and 962, respectively, by almost equal contact forces caused by elastic forces of the spring portions 910 and 911, whereby the contact pads of the printed circuit boards 961 and 962 are electrically connected via the contacts 901.
As shown in FIG. 13, the holding portion 904 is located on an imaginary straight line S (straight line parallel to the connection direction D) connecting the pair of contact portions 902 and 903. Since this structure is employed, to connect the printed circuit boards 961 and 962 using the connector, enough spaces for both the spring portions 910 and 911 of the contact 901 to be bent (space for preventing displacement of the contact portions 902 and 903 from being restricted by the holding portion 904 when the printed circuit boards 961 and 962 are connected using the connector) are required to be provided between the contact portions 902 and 903, and the opposite ends of the holding portion 904 (opposite ends in the connection direction D), respectively. To ensure the spaces, the connector is press-fitted in the press-fitting hole 921 of the frame 920.
Unless the frame 920 is used, to ensure a predetermined contact force, it is required to make the length of the contact accommodation space 952 in the connection direction D equal to the length of the press-fitting hole 921 in the connection direction D, which results in an increase in the size of the connector.